A roller is provided that is configured to support of a rotary platform. The roller includes at least one side flange including an inner surface, a rolling surface to be in contact with a flat running surface of an upper rail member fixedly connected to the rotary platform and a flat running surface of a lower rail member stationary arranged. The roller includes a circumferential recess connecting the rolling surface to the inner surface of the side flange and that the circumferential recess has a depth such that the flat running surfaces of the upper rail member and the lower rail members are out of contact with a bottom surface of the circumferential recess at a potential angle deviation between the flat running surfaces of the rail members and a rotation axis of the roller.